(a) Field of the Invention
The present invention is related to a circuit control technology for portable electronic devices including notebook, and more particularly, to one that allows an external device access to a storage device in the host through a sub-circuit configuration when the portable electronic device is in power off status.
(b) Description of the Prior Art
Portable electronic devices including the notebook today are gradually capable of providing all those function a desktop computer can do thanks to the rapidly upgraded chip manufacturing technology and operation efficacy. Compared to the desktop computer, the notebook gives features of being compact and provided with built-in DC source particularly ideal for persons always on the road. Furthermore, in terms of the state of art, the efficacy and operation speed of the microprocessor adapted to the notebook are comparable to that of the desktop. However, as restricted by its structural type, power consumption and overheating during the normal power on operation affect the usable time and operation efficacy of the notebook.
Furthermore, though provided with the feature of portability, the storage device (e.g., a hard disk) can only be activated through the microprocessor and the operation of related circuit with the main system in normal power on status. Therefore, data created in the storage device is accessible only when the device is in its normal power on status. For example, if the user desires to access to the data of music format (e.g. MP3 data) through the portable electronic device (e.g., a notebook), the MP3 data can only be read to play the music with the notebook in power on status. By doing so, it creates the problems of excessive power consumption and overheating to cause inconvenience in the use of the notebook. Besides, the monitor of the notebook must be maintained lifted up during the power on status, and that creates placement and accommodation problems to the user if he just needs to listen to the music or to execute some simple task of data access.